I-365 is a byproduct formed during the manufacture of I-141b, a replacement for trichlorofluoromethane as a blowing agent. Since I-365 is a solvent and precursor for other chemicals, a method for its recovery is needed. Separation by conventional distillation means is extremely difficult, however, since I-365 and I-141b form an azeotrope.
While liquid-liquid extraction has been reported in U.S. Pat. No. 4,031,148 for separating chlorinated hydrocarbons by the use of water-miscible solvents and 0%-50% water, applicant is not aware of literature which discloses liquid-liquid extraction for separating HFC's (hydrofluorocarbons) such as I-365 from HCFC's (hydrochlorofluorocarbons) such as I-141b. Also, as noted in column 1, lines 53-56 of said U.S. Pat. No. 4,031,148, and as demonstrated by copending application Ser. No. 07/751,014, filed on even date herewith, it is impossible to foresee which extraction agents will enable the separation of any two substances.